Topographic anatomy and CT correlations in the untreated glioblastoma multiforme

ECM-mediated glioma cell invasion

Cell adhesion receptors of the integrin superfamily, CD44, and adhesion receptors of the immunoglobulin superfamily are expressed by high-grade astrocytic tumors of the central nervous system. These receptors are critical for the invasion of these tumors in the nervous system. Glioma cells utilize these receptors to adhere to and migrate along the components of the extracellular matrix, which is uniquely distributed and regulated within the brain and the spinal cord. For this reason, glioma cell invasion into the adjacent brain tissue is dependent on the interaction of glioma cells with the extracellular matrix. The receptor-ECM component interaction is discussed, focusing on the role of cell adhesion molecules of the integrin family and CD44 in glioma cell adhesion and invasion.

Bihemispheric malignant glioma: one size does not fit all

Recurrence of malignant glioma following radiotherapy most commonly occurs in close proximity to the original contrast enhancing CT/MRI tumor volume. For this reason current radiation planning favors focal radiotherapy fields designed to cover the preoperative tumor contrast enhancing volume +/- surrounding edema with a 2-4 centimetre margin. Two patients with bifrontal malignant gliomas treated with such radiotherapy fields experienced out of field tumor progression while on treatment. Posterior extension along the corpus callosum, not evident on pretreatment imaging, was hypothesized as the cause of the geographic miss. The literature documenting recurrence patterns of malignant glioma following radiotherapy support focal field radiotherapy fields for most patients with malignant glioma. Reporting bias may exist in the literature, however, due to the whole brain radiotherapy used in older series reporting recurrence patterns and exclusion of patients with bihemispheric or more locally extensive tumors in more modern series. Tumor location and pattern of growth at presentation may be important factors in predicting patterns of spread and relapse after radiotherapy.

Effects of resective surgery for left-sided intracranial tumours on language function: a prospective study

BACKGROUND

Although language disorders occur in about 50% of patients with a left hemispheric tumour and are a significant cause of morbidity, the effects of resective neurosurgery and their relation to tumour pathology are unclear. We report the immediate effects of resective surgery on language functions in a heterogeneous group of patients with left-sided intracranial tumours.

METHODS

40 patients were studied. The Western Aphasia Battery (WAB) and Boston Naming Test (BNT) were administered preoperatively and before discharge following resective neurosurgery. Dexamethasone dose at time of testing was recorded, as was time taken to complete the tests, and tumour neuropathology.

FINDINGS

15 patients with normal aphasia quotients and language quotients before resective surgery all had normal quotients postoperatively. 25 who were dysphasic (ie, aphasia quotient <93.8) preoperatively showed significant postoperative improvements in both their mean aphasia quotient (from 81.8 to 89.1, p=0.004) and their mean language quotient (from 73.4 to 85.4, p=0.001), though 13 remained dysphasic. Two of the 25 dysphasic patients had their WAB scores lowered by tumour resection. The findings and postoperative changes in BNT scores were almost identical to the pattern of those in WAB scores. At second assessment, dexamethasone therapy was significantly (p<0.01) lower than preoperative dose (reduction from mean 10.3 mg/day to 0.7 mg/day in the dysphasic group). Patients with glioblastoma were more likely to have lower aphasia quotients, language quotients, and BNT scores than patients with anaplastic glioma, metastasis, or meningioma. Although the glioblastoma group had the greatest improvements in WAB operative scores, 57% remained dysphasic after resective surgery. Two additional patients declined postoperative assessment.

INTERPRETATION

Resective surgery for left-sided intracranial tumours significantly improves language function in dysphasic patients, and is unlikely to impair language functions in non-dysphasic patients. Dysphasia and its response to resective surgery are related to the tumour neuropathology.

Quantitative analysis of microvascular changes in diffuse astrocytic neoplasms with increasing grade of malignancy

Because glioblastoma multiforme (GBM) frequently shows striking, glomeruloid microvascular proliferation (MVP), this tumor has become a strong candidate for anti-angiogenic therapy. However, the efficacy of anti-angiogenic treatment may rather be determined by the extent of classic angiogenesis with the formation of delicate microvascular sprouts. Therefore, this study differentially quantifies the microvascular changes in supratentorial diffuse astrocytic neoplasms by computerized image analysis of histological sections in which the microvessels were highlighted by a combined anti-collagen IV/MIB-1 staining. Four microvascular parameters (number, area, perimeter, diameter), the cellularity of the glial tissue, and the MIB-1 labeling index were assessed in biopsies of astrocytoma (A, n = 13), anaplastic astrocytoma (AA, n = 14), and GBM (n = 20), and in normal cerebral cortex (n = 7) and white matter (n = 7). In As and AAs, the microvascular parameters were not significantly different from each other, and the microvascular changes were generally limited compared with WM and CX. In contrast, in GBMs the microvascular parameters were highly variable, and their overall mean value was significantly increased compared with As and AAs (ranging from 1.3x for vessel diameter to 3.3x for vessel area). Our study indicates that not only glomeruloid MVP, but also classic angiogenesis, occurs mainly and only locally in GBMs. Thus, this study provides evidence that As and AAs are not good candidates for anti-angiogenic therapy. The efficacy of such therapy for GBMs awaits further evaluation.

Stimulation of extracellular matrix components in the normal brain by invading glioma cells

Malignant gliomas are characterized by an extensive invasion of tumor cells into the normal brain parenchyma. A substantial amount of data indicates that cell movement in general is regulated by specific interactions between extracellular matrix components and specific cell-surface receptors. In the present work, multicellular spheroids from 4 human glioma cell lines (U-373Mg, A-172Mg, U-251Mg and HF-66) were confronted with normal rat brain cell aggregates in vitro, which resulted in a progressive invasion of tumor cells into the brain aggregates. The co-cultures were then sectioned and immuno-stained for specific extracellular matrix components (laminin, fibronectin and collagen type IV) and for specific cell-surface receptors which bind to these components (integrins beta1, beta4, alpha3, alpha6). In addition, flow-cytometric measurements and Northern blot analyses showed expression of several different integrins within the cell lines. The alpha3 subunit was expressed strongly in all cell lines. Whereas the beta1 subunit was expressed weakly in exponentially growing monolayer cultures, it showed a pronounced expression in multicellular spheroids, indicating that the integrin expression may vary depending on the micro-environment within a tumor. Furthermore, normal brain tissue was able to produce laminin when confronted with the glioma cells, which also was observed for fibronectin and collagen type IV. The relevance of our observations to the in vivo situation was investigated further by immuno-staining 5 human glioma biopsy samples for laminin. In some areas of the tumors, specific deposits of laminin were observed. In conclusion, we have shown that normal brain tissue has the ability to produce extracellular matrix components, such as laminin, collagen type IV and fibronectin, when confronted with invading glioma cells. Our results show that the glioma cells express specific integrins which can interact with these extracellular matrix components. Such interactions may facilitate tumor cell migration and invasion.

High-dose conformal radiotherapy influenced the pattern of failure but did not improve survival in glioblastoma multiforme

BACKGROUND AND PURPOSE

Although glioblastoma multiforme is clearly radiation-resistant, there is evidence of a dose-dependent response relationship. The purpose of the study was to evaluate the impact of higher dose by rotational multileaf collimator (MLC) conformal radiation therapy.

MATERIALS AND METHODS

From 1984 to 1995, 38 consecutive cases with intracranial glioblastoma multiforme were treated using the rotational MLC conformal therapy. There were 25 men and 13 women with a median age of 47 years (12-73 years, mean 46.5 years). Median Karnofsky performance score was 80 (30-100, mean 78.2). Median tumor volume was 64 cc (8-800 cc, mean 110.3 cc). All underwent surgical intervention (only biopsy in 1, partial resection in 13, subtotal resection in 21, and gross total resection in 3). Radiation dose to was 60 to 80 Gy (median 68.5 Gy, mean 68.3 Gy) in 21 patients treated before 1990 and 90 Gy in the 17 patients thereafter. Biweekly i.v. chemotherapy was also administered for both arms.

RESULTS

The 1-year, 2-year, 5-year, and 10-year overall survival rates were 75%, 42%, 20%, and 15%, respectively. Univariate analysis showed the initial tumor volume, residual tumor volume, and Karnofsky performance score were statistically significant factors for survival. Only the residual tumor volume was statistically significant by multivariate analysis. The 5-year survival rate of patients with residual tumors of 5 cc or less in volume was as good as 37%. Survival of the 90-Gy Group appeared inferior to that of the Low-Dose Group, though no statistical difference was seen (the 3-year survival was 40% vs. 22%). Local failure was observed in 16 of the 19 recurrences in the Low-Dose Group, whereas it was observed in only 4 of the 13 recurrences in the 90-Gy Group. The difference in pattern of failure was statistically significant. Two patients of the High-Dose Group developed radiation necrosis and one died of it.

CONCLUSIONS

The high-dose conformal radiotherapy did not improve survival in the disease, but did change the pattern of failure.

Specific matrix metalloproteinase profiles in the cerebrospinal fluid correlated with the presence of malignant astrocytomas, brain metastases, and carcinomatous meningitis

BACKGROUND

Detection in tumor tissue of specific matrix metalloproteinases (MMPs), particularly gelatinases A and B, correlates with the grade and aggressiveness of primary and metastatic brain tumors. The ability to detect these enzymes in the cerebrospinal fluid (CSF) would be a minimally invasive method of evaluating brain tumors.

METHODS

CSF from 66 patients with white blood cell counts of < or = 5 microL were analyzed for the presence of gelatinolytic activity by zymography. Twenty-nine patients had malignant astrocytomas, 10 had brain metastases from systemic malignancies, 4 had systemic cancer not involving the central nervous system, 4 had nonmalignant neurologic diseases, and 19 were healthy controls. Fifteen CSF samples had positive cytologies. The zymographic results were retrospectively correlated with clinical information and CSF cytologic data.

RESULTS

CSF from all patients with malignant astrocytomas or brain metastases contained precursor gelatinase A (pMMP2) and precursor gelatinase B (pMMP9), whereas control CSF contained only pMMP2. All patients with positive CSF cytologies had activated MMP2. A similar correlation was observed between the presence of activated MMP9 and positive CSF cytology.

CONCLUSIONS

The precursor and activated forms of gelatinases A and B can be detected in the CSF of patients with primary and metastatic brain tumors. The distribution of gelatinase activity in CSF distinguishes patients with malignant gliomas or brain metastases from those without brain tumors, and distinguishes patients with meningeal carcinomatosis from those without CSF spread of tumor, regardless of their brain tumor status. Analysis of MMPs in the CSF may be a sensitive technique for diagnosing CNS tumors and provide an early indication of tumor recurrence. This technique may also provide longitudinal information that would be useful in evaluating ongoing treatment and predicting tumor behavior.

Cytostatic Agents in the Management of Malignant Gliomas

BACKGROUND: Cytotoxic therapy for malignant gliomas is limited by poor delivery and drug resistance, and local therapy is ineffective in managing migratory cells. However, recent developments in malignant glioma therapy involve trials of cytostatic rather than conventional cytotoxic agents. METHODS: The biology of the brain extracellular matrix, tumor invasion, and angiogenesis are reviewed, and the cytostatic agents that inhibit matrix metalloproteinases, angiogenesis, cell proliferation, and signal transduction are discussed, as well as studies of the angiogenic and migratory capacity of malignant brain tumors. RESULTS: Two specific and interrelated areas, anti-invasion (migration) and anti-angiogenesis, are potential areas to develop new treatment strategies. Tumor invasion and angiogenesis are important components of the spread and biologic effects of malignant gliomas. Several proteinase inhibitors are in clinical trial, as well as anti-angiogenic agents and signal transduction cascade inhibitors. CONCLUSIONS: Biologic control of brain tumor cell populations may offer a new management approach to add to currently available management options for malignant brain tumors.

[3-Dimensional irradiation planning in brain tumors. The advantages of the method and the clinical results]

PURPOSE

Radiotherapy became an important component in the treatment of brain gliomas. The aim of this study is to analyse several advantages of the three-dimensional conformal radiation therapy in comparison with a two-dimensional conventional technique and to present the clinical results of 43 patients with brain gliomas treated according to a three-dimensional planning.

PATIENTS AND METHOD

Between January 1994 and December 1995, 43 patients with malignant brain gliomas (WHO III and IV) were treated in our department according to a three-dimensional treatment planning. The patients received a total irradiation dose of 60 Gy, 2 Gy/day, 5 days/week. The rate of survival was analysed in relation with the known prognostical factors: histology, Karnofsky index, age, resection status. In 10 patients a three-dimensional treatment planning was compared with a conventional two-dimensional planning: the volume of the normal brain tissue irradiated to high dose levels (95% isodose) and the normal tissue complication probability (NTCP) for the brain by Kutcher and Lyman were comparatively analysed.

RESULTS

The survival rate for the whole group was 14 months. The histology of the tumor, age, Karnofsky index and resection status were important prognostical factors. The three-dimensional planning allows a 15 to 20% reduction in the volume of normal brain tissue irradiated to high dose levels (95% isodose). The NTCP is significantly lower using the three-dimensional technique (range 0.03% to 13%), in comparison with the two-dimensional conventional technique (range 0.1% to 26%). The value of NTCP increases with tumor volume.

CONCLUSIONS

Concerning the tumor control and survival rate, the three-dimensional treatment planning shows no advantages compared to the standard conventional methods. The main advantage of the three-dimensional treatment planning is the possibility to spare normal brain tissue. The possibility to integrate mathematical models in the evaluation of the therapy could give this technique new dimensions.

Immediate postoperative CT contrast enhancement following surgery of cerebral tumoral lesions

PURPOSE

Our goal was to evaluate the immediate postoperative contrast enhancement behavior of cerebral lesions and to gain further information about contrast enhancement in patients under general anesthesia.

METHOD

In the early postoperative period, CT scans with the without contrast medium were performed in 46 patients. The time interval between surgery and postoperative CT imaging ranged from 1 to 7.5 h (mean 4 h). Nineteen patients were under general anesthesia during CT investigation.

RESULTS

In the early postoperative period, contrast medium leakage into the tumor resection cavity was noted In 14 patients (30%). Another phenomenon that was observed was the appearance of a strong demarcation and distinct contrast of gray against white matter in 24 patients (52%). This characteristic, global contrast enhancement of the cerebral cortex, occurred in 17 of 19 patients (89%) investigated under general anesthesia.

CONCLUSION

In immediate postoperative CT scans, contrast medium leakage due to extravasation of contrast medium into the tumor resection cavity can be detected early. Moreover, a global contrast enhancement of the cerebral cortex can be detected as a frequent pattern in patients investigated under general anesthesia.

Whole-body hyperthermia and ADPRT inhibition in experimental treatment of brain tumors

Malignant primary brain tumors have hitherto been incurable. One reason for this may be the migrating tumor cells that spread into the surrounding normal brain, creating the basis for inevitable recurrences. Therefore, local therapy may have a temporary effect, but for a cure, the treatment must reach all the tumor cells. Whole-body hyperthermia (WBH) is such a general treatment, which we have studied in a rat glioma model. Cells of the RG2 rat glioma cell line were inoculated in the right caudate nucleus of Fischer-344 rats, which were then either controls or treated with WBH, induced by a radiant heat device for 4-5 sessions of 30 min at body temperature 42 degrees C (rectal), and/or nicotinamide (NAM), an effective radiosensitizer in animal tumor models and an inhibitor of ADPRT (poly adenosine diphosphate ribosyl transferase), a chromatin-bound enzyme suggested to be important in the DNA repair system. We have shown that WBH 42 degrees C alone, or in combination with NAM, has no effect upon tumor growth if a larger number of RG2 cells (5,000) are inoculated. If only 1,000 cells are inoculated, a significant inhibitory effect (p < 0.05) is observed on tumor growth as compared to the untreated control animals. Thus, WBH is feasible, and in some circumstances effective, in a rat glioma model. WBH in combination with other therapies influencing cell metabolism may be of value in future postoperative treatment of human malignant brain tumors.

Implantation of C6 astrocytoma spheroid into collagen type I gels: invasive, proliferative, and enzymatic characterizations

A three-dimensional model has been developed in which C6 astrocytoma spheroids of defined sizes are embedded into collagen type I gels. The authors have monitored cell invasive behavior; obtained quantitative data on cell invasion, proliferation, and enzymatic activity; assessed cell-cell interactions by altering the spheroid size used; and studied cell-matrix interactions by modifying the matrix components. Their results show that C6 astrocytoma cells detach from the spheroid surface and invade the gel as single cells by means of a system that appears to be dependent on metalloprotease function. These invasive cells have a low proliferative index. Larger spheroids with central hypoxic microregions possess cells that invade the gel at faster rates; this could be correlated with the release of increased collagen type I degrading activity. Extracellular matrix proteins, such as laminin, fibronectin, and collagen type IV have no significant influence on invasive activity, whereas hyaluronic acid decreases and human central nervous system myelin increases invasion. New strategies directed at the treatment of malignant gliomas must take into account the subpopulation of malignant cells located long distances from the major tumor mass. The spheroid invasion model may provide specific insights into the behavior of these invasive cells.

Clonal analysis of gliomas

In malignant gliomas, the characteristically heterogeneous features and frequent diffuse spread within the brain have raised the question of whether malignant gliomas arise monoclonally from a single precursor cell or polyclonally from multiple transformed cells forming confluent clones. Although monoclonality has been shown in surgically resected tissues, these may not include the full spectrum of patterns seen on autopsy material. Little is known about the clonality of low-grade gliomas from which malignant gliomas may sometimes arise. We sought to investigate the clonality of low-grade and malignant gliomas by using and comparing surgical and autopsy material with a Polymerase chain reaction (PCR)-based assay for nonrandom X chromosome inactivation. For that, purpose, archival surgical and autopsy material from 15 female patients (group A) (age 4 to 73 years; median, 45) with malignant gliomas (12 glioblastomas, one gliosarcoma, one anaplastic oligoastrocytoma, one gliomatosis cerebri), surgical material only from 21 female patients (group S) (age 6 to 78 years; median, 60) with low-grade and malignant gliomas (four low-grade astrocytomas, three oligoastrocytomas, two anaplastic astrocytomas, one gemistocytic astrocytoma, four oligodendrogliomas, seven glioblastomas) were analyzed. In group A, representative areas (mean = 5/patient; median = 7) were microdissected from tissue sections and assayed by PCR amplification of a highly polymorphic microsatellite marker locus of the human androgen receptor gene (HUMARA) in the presence of alpha32P with and without predigestion with a methylation-sensitive restriction enzyme (HhaI). Products were resolved by denaturing gel electrophoresis and autoradiographed. In group S, selected tumor areas were used for the assay. Each patient's normal brain tissue was used for control. The band intensity of alleles were measured by densitometric scanning. In group A, 13 of 15 cases were informative (heterozygous). The same pattern of nonrandom X chromosome inactivation was present in all areas of solid dense and moderate tumor infiltration in eight including all components of the gliosarcoma. Two of eight also showed focal loss of heterozygosity (LOH). One of 13 presented global LOH. Two of 13 showed microsatellite instability, one of which in a patient with Turcot syndrome, the other in gliomatosis cerebri. Opposite skewing patterns were seen in distant areas of gliomatosis cerebri consistent with oligoclonal derivation. Clonality remained indeterminate in one glioblastoma and in the anaplastic oligoastrocytoma because of skewed lyonization in the normal control. In group S, 19 of 21 cases were informative. Fifteen of 19 were monoclonal (four low-grade astrocytomas, one anaplastic astrocytoma, one gemistocytic astrocytoma, two oligodendrogliomas, one oligoastrocytoma, six glioblastomas). Four of 19 were indeterminate. We conclude that (1) Low-grade and malignant gliomas are usually monoclonal tumors, and extensively infiltrating tumors must result from migration of tumor cells (2) Gliomatosis cerebri may initiate as an oligoclonal process or result from collision gliomas (3) Biphasic gliomas likely arise from a single precursor cell. (4) LOH at the HUMARA locus is probably related to partial or complete deletion of an X-chromosome, which occurs in malignant gliomas during clonal evolution.

Supratentorial malignant gliomas in childhood: a single institution perspective

BACKGROUND

A retrospective study evaluated the clinical characteristics, prognostic factors, and outcome of patients with newly diagnosed supratentorial malignant gliomas treated with preirradiation chemotherapy.

METHODS

Of 41 patients with supratentorial malignant gliomas accrued between 1984-1994, all had neuroimaging documentation of the extent of resection and 37 had complete neuraxis staging prior to treatment; 80% were treated with one of a variety of neoadjuvant chemotherapy regimens.

RESULTS

Thirteen patients had anaplastic astrocytoma (AA), 25 had glioblastoma multiforme (GBM), and 3 had anaplastic oligodendroglioma. Gross total resection (GTR) was performed in 10 patients, subtotal resection (STR) in 22 patients, and biopsy (Bx) alone in 9 patients. For the entire group the 3-year overall and progression free survivals were 35 +/- 8% and 18 +/- 6%, respectively. Tumor recurrence was dominantly local. However, 9 patients with initially local disease failed at a distant neuraxis site, giving a 26 +/- 7% actuarial risk of dissemination at 3 years. The only significant prognostic factor was extent of tumor resection: patients who underwent GTR survived longer than those who underwent STR or Bx (P = 0.004). Histology (GBM vs. AA), age, and the use of enhanced local dose radiation therapy (brachytherapy or stereotactic irradiation) did not affect survival.

CONCLUSIONS

Neoadjuvant chemotherapy was not associated with a survival rate significantly different from that observed in adjuvant chemotherapy studies. Systematic neuraxis staging at diagnosis and recurrence revealed a rate of neuraxis dissemination as a component of recurrence that was higher than previously reported; the utility of craniospinal irradiation in preventing isolated dissemination remains uncertain.

Angiogenesis in brain tumors; pathobiological and clinical aspects

Angiogenesis is the outgrowth of new blood vessels from the preexistent vasculature. In 1971, Folkman hypothesized that solid tumors are dependent on angiogenesis for sustained growth and that anti-angiogenic treatment is a potential antineoplastic therapy. Because glioblastoma multiforma (GBM) frequently shows florid microvascular proliferation (MVP), this tumor has been considered since then as a suitable candidate for such treatment that attempts to eradicate or control a neoplasm by interfering with its blood supply. Indeed, in animal models the growth of glioma xenografts can be inhibited by targeting the angiogenic process. However, unlike many glioma xenografts, human infiltrating gliomas such as GBMs have a diffuse infiltrative growth pattern, and preexistent vessels may suffice to provide many tumor cells with much of their blood supply, particularly in the critical peripheral infiltrative margins. Thus, while attractive in concept, anti-angiogenic therapy of GBM must address the anatomic vascular realities of this neoplasm. Even if anti-angiogenic therapy ultimately has a role in infiltrative neoplasms, there are a host of other intracranial neoplasms whose discrete architecture might make them attractive candidates for anti-angiogenic therapy. This review summarizes the angiogenic process in GBM and suggests other types of tumors for which the efficacy of anti-angiogenic therapy might be studied.

Interstitial fluid flow along white matter tracts: a potentially important mechanism for the dissemination of primary brain tumors

High grade astrocytomas remain incurable even though these tumors often appear localized on modern imaging studies, rarely metastasize to systemic sites, and can be aggressively treated with surgery and radiation therapy. Recent data suggest that the dissemination of astrocytoma cells along white matter tracts to distant regions of the brain may be responsible for the poor survival of these patients and the limited impact of local therapies. Movement of astrocytoma cells along these white matter tracts can be active or passive in nature. To study the potential for tumor dissemination by bulk flow of interstitial fluid resulting from peritumoral edema. 20 microL of tritiated inulin, Evans Blue, and rat albumin were injected stereotactically into the right frontal lobe and the left temporal lobe at the gray-white matter junction in Sprague-Dawley rats. Six hours later, the rats were sacrificed and the brains were removed, frozen and prepared for quantitative autoradiography and histologic analysis. Interstitial flow rates were calculated from the autoradiographs, and flow pathways were determined from the movement of Evans Blue, inulin and histologic data. In each animal injected in the frontal lobe, Evans Blue and inulin were primarily confined to large ipsilateral white matter tracts and extended from the frontal injection site to the occipital lobe. The average interstitial fluid flow rate in the association fibers of the external capsule was 0.86 mm/hr. In contrast, the animals receiving temporal lobe injections had Evans Blue and inulin confined to the temporal lobe. The average interstitial fluid flow rate in the white matter tracts of the temporal lobe was 0.61 mm/hr. The rapid and preferential flow of interstitial fluid along white matter tracts and the differences in the clearance of extracellular fluid observed between the frontal and temporal lobes may have important clinical implications. These data suggest that aggressive treatment of peritumoral edema, expansion of radiotherapy ports, and consideration of the location of the tumor in treatment planning may improve therapeutic outcomes for some patients. An improved understanding of the mechanisms of tumor dissemination is crucial to designing more effective therapeutic approaches for patients with this devastating malignancy.

Isolation and characterization of human malignant glioma cells from histologically normal brain

Brain invasion prevents complete surgical extirpation of malignant gliomas; however, invasive cells from distant, histologically normal brain previously have not been isolated, cultured, and characterized. To evaluate invasive human malignant glioma cells, the authors established cultures from gross tumor and histologically normal brain. Three men and one woman, with a mean age of 67 years, underwent two frontal and two temporal lobectomies for tumors, which yielded specimens of both gross tumor and histologically normal brain. Each specimen was acquired a minimum of 4 cm from the gross tumor. The specimens were split: a portion was sent for neuropathological evaluation (three glioblastomas multiforme and one oligodendroglioma) and a portion was used to establish cell lines. Morphologically, the specimens of gross tumor and histologically normal brain were identical in three of the four cell culture pairs. Histochemical staining characteristics were consistent both within each pair and when compared with the specimens sent for neuropathological evaluation. Cultures demonstrated anchorage-independent growth in soft agarose and neoplastic karyotypes. Growth rates in culture were greater for histologically normal brain than for gross tumor in three of the four culture pairs. Although the observed increases in growth rates of histologically normal brain cultures do not correlate with in vivo behavior, these findings corroborate the previously reported stem cell potential of invasive glioma cells. Using the radial dish assay, no significant differences in motility between cultures of gross tumor and histologically normal brain were found. In summary, tumor cells were cultured from histologically normal brain acquired from a distance greater than 4 cm from the gross tumor, indicating the relative insensitivity of standard histopathological identification of invasive glioma cells (and hence the inadequacy of frozen-section evaluation of resection margins). Cell lines derived from gross tumor and histologically normal brain were usually histologically identical and demonstrated equivalent motility, but had different growth rates.

Local spread of malignant neuroepithelial tumors

A short review of invasiveness of primary malignant neoplasms in the nervous system is given. Invasiveness implies progressive spread and destruction locally, which eventually leads to a fatal outcome in the patient. In particular, the malignant cells are able to rapidly migrate over large parts of the brain. This process includes the capacity to adhere to a substratum, usually constituted by the various components of the extracellular matrix, followed by detachment and migration. Anatomical structures and local regulatory factors in the brain influence the direction and extent of this migration. Several model systems are now available for monitoring the aggressiveness of such tumours both in vivo and in vitro, and different phenotypic properties characteristic of invasive cells have been elucidated. Although still in its infancy, and currently as an experimental approach, anti-invasive therapy may in the future be an interesting alternative to conventional chemotherapy of brain tumours.

Early delineation of cerebral glioma using amino acid positron tracers

A 56-yr-old housewife with cerebral astrocytoma was reported with positron emission tomography findigns using 11C-methyl-L-methionine (11C-Met) and 18F-fluorophenylalanine (18F-Phe) tracers. 11C-Met and 18F-Phe accumulated intensely in tumor lesions, although CT scans showed only a foggy low-density area. Five years and one month after, an enhancing mass appeared on CT scans. Thus, amino acid tracers may play a important role in the early diagnosis of gliomas.

Polymeric controlled-release amsacrine chemotherapy in an experimental glioma model

The purpose of this study was to fabricate and investigate amsacrine containing polymeric rods for use in interstitial chemotherapy of malignant glioma. Ethylene vinyl acetate copolymer (EVAc) rods containing 40% amsacrine (AMSA) were fabricated successfully with an extrusion method. In vitro kinetic studies revealed a high level of reproducibility of the production process. The release of AMSA showed a biphasic pattern consistent with a matrix-type controlled-release system with an initial more rapid release rate followed by a slower and more linear release phase. Release of AMSA was observed for over 6 months and the rods continue to release in a stable fashion. In vitro studies using rat glioma (RG2) in cell culture showed that cells treated with AMSA released from the rods were killed in a dose dependent manner indicating that AMSA incorporated into the polymer remained biologically active. In vivo studies of rats with single AMSA rods implanted five days after RG2 tumour implantation revealed histological evidence of an anti-tumour effect as well as an increased survival (p < 0.0003). The mean survival of the amsacrine treated rats was 78 days with 50% still remaining alive > 5 months after implantation. All control animals developed tumours and died within 15-19 days after tumour implantation (mean = 17 days). Amsacrine implanted animals showed no significant histological or clinical evidence of toxicity. We conclude that amsacrine containing EVAc rods can be safely and efficaciously use against the RG2 experimental glioma in a rat model and warrant further investigation.

Stimulation of glioma-cell migration by laminin and inhibition by anti-alpha3 and anti-beta1 integrin antibodies

An induction of laminin in the confrontation zone between tumor cells and normal brain tissue has been observed in our model systems in vivo and in vitro. In order to study the effects of ECM components on glioma-cell migration and invasion, we have used 2 lacZ-transfected glioma cell lines, AN1/lacZ and U-251 /lacZ. Cell migration from multicellular spheroids was studied using different types of media: DMEM with 10% serum, Ultra Culture medium, and filtrated DMEM with serum in which the protein fraction > 100 kDa had been removed by ultrafiltration. Laminin, fibronectin and collagen type-IV were individually added to the different media, and cell migration from the spheroids was studied. The results show that cell migration in both cell lines, was stimulated by laminin and fibronectin. Collagen type-IV stimulated only cell migration of U-251/lacZ cells. Scanning electron microscopy revealed an extensive change in cell shape as a result of laminin stimulation. Flowcytometric studies showed that both AN1/lacZ and U-251/lacZ strongly express the alpha3 beta1 integrin receptor, which can bind to several ECM components (laminin, fibronectin, collagen). Immunofluorescence microscopy demonstrated that the same integrin sub-units were expressed in multicellular spheroids. When monoclonal antibodies to alpha3 and beta1 were added to the laminin-stimulated cultures, cell migration was significantly reduced. This indicates that the alpha3 beta1 integrin receptor plays an important role during glioma-cell migration.

Treatment of advanced CNS malignancies with the recombinant adenovirus H5.010RSVTK: a phase I trial

Primary CNS malignancies are responsible for approximately 12,000 deaths annually in the United States. There has been little change in the outcome for adults with malignant brain tumors over the past few decades, despite improvements in surgical techniques and advances in radiation therapy. These tumors are uniformly fatal one to two years after diagnosis. The morbidity and mortality of this disease arise from the effects of a locally invasive, non-metastasizing lesion. The patients may suffer from seizures, paralysis, incoordination, aphasia, confusion, memory loss, sensory deficits or visual loss, depending on the regions of the brain affected. In addition, they usually require large doses of corticosteroids early and late in their illness, and may experience disabling side effects of this treatment, such as edema, proximal myopathy, diabetes, fungal infections or deep vein thrombosis. Few patients in the older age group are able to work after the diagnosis. Most of the patients are incapable of self-care for several months before death. The localized transfer of new genes into cancer cells potentially permits the expression of proteins with specific biologic functions that may provide a means to alter the biology of tumor growth through a variety of mechanisms including increasing tumor immunogenicity, inducing the local expression of toxic agents, and sensitization of tumors to chemotherapeutic agents. Gene therapy with the transfer of the drug susceptibility gene Herpes virus thymidine kinase (HSV-TK) has shown promise in a number of animal models, including CNS tumors. This study will evaluate the use of adenovirus-mediated transfer of the HSV-TK gene into primary human brain tumors followed by systemic treatment with ganciclovir. The goals of this phase I study are to evaluate the overall safety and efficacy of this treatment and to gain insight into the parameters that may limit the general applicability of this approach. In this phase I study, patients with recurrent gliomas will receive stereotactic-guided injections of the virus into the brain tumor, followed by intravenous ganciclovir for 14 days. Patients eligible to undergo a palliative debulking procedure will receive the same treatment followed by resection on day 7. At the time of resection a second dose of virus will be administered intra-operatively into the residual, unresectable portion of the tumor, and intravenous ganciclovir will be continued for additional 14 days. Tissue removed at the time of resection will be analyzed for evidence of adenovirus infection, thymidine kinase expression and signs of inflammation. The size and metabolic activity of all tumors will be followed by volumetric MRI scans and Position Emission Tomography Scans, respectively. Patients will be enrolled in groups of three, with each group receiving successively larger doses of adenovirus. This study will quantify the toxicity of this therapy, and provide evidence as to the duration of transgene expression and virus induced inflammation.

Glioma invasion in the central nervous system

Invading glioma cells seem to follow distinct anatomic structures within the central nervous system. Tumor cell dissemination may occur along structures, such as the basement membranes of blood vessels or the glial limitans externa, that contain extracellular matrix (ECM) proteins. Frequently, invasive glioma cells are also found to migrate along myelinated fiber tracts of white matter. This behavior is most likely a consequence of using constitutive extracellular ligands expressed along the pathways of preferred dissemination. The extracellular space in anatomic structures, such as blood vessel basement membranes or between myelinated axons, is profoundly different, thus suggesting that glioma cells may be able to use a multiplicity of matrix ligands, possibly activating separate mechanisms for invasion. In addition, enzymatic modification of the extracellular space or deposition of ECM by the tumor cells may also create a more permissive environment for tumor spread into the adjacent brain. Tumor cell invasion is defined as translocation of neoplastic cells through host cellular and ECM barriers. This process has been studied in other cancers, in which a cascade of events has been described that involves receptor-mediated matrix adhesion, degradation of matrix by tumor-secreted metalloproteinases, and, subsequently, active cell locomotion into the newly created space. Although some of these mechanisms may play an important role in glioma invasion, there are some significant differences that are mainly the result of the profoundly different composition of the extracellular environment within the brain. This review focuses on the composition of central nervous system ECM and the recent evidence for the use by glioma cells of multiple invasion mechanisms in response to this unique environment.

Preserved function in brain invaded by tumor

OBJECTIVE

Intrinsic brain tumors can arise within regions of the cortex that are essential to language, motor, and somatosensory functions. Although it is commonly thought that such tumors can be safely resected, as long as the resection is limited to grossly abnormal cortex, functional mapping of the cerebral cortex during tumor resection does not support this contention.

METHODS

We report our experience with 14 patients (9 men, 5 women; median age, 43 yr) with intrinsic brain tumors of varying degrees of malignancy (four glioblastomas multiforme, four anaplastic astrocytomas, two anaplastic oligodendrogliomas, one anaplastic mixed glioma, three gangliogliomas). Cortical mapping was performed either intraoperatively (n = 11) or extraoperatively via intracranial electrodes (n = 3).

RESULTS

Tumors were found to grossly invade functioning cortices (frontal lobe language cortex, four tumors; temporal lobe language cortex, five tumors; motor cortex, four tumors; somatosensory cortex, one tumor). The gross invasion of functional cortex by tumor limited safe resection in all patients. Three patients experienced transient postoperative deficits caused by the proximity of the resection to functional cortex. One patient suffered a delayed postoperative hemorrhage, with resultant persistent motor aphasia.

CONCLUSION

Intrinsic brain tumors grow by infiltration of normal brain. Consequently, brain that appears to be abnormal may remain functional, thus precluding safe tumor resection.

A mathematical model of glioma growth: the effect of extent of surgical resection

We have developed a mathematical model based on proliferation and infiltration of neoplastic cells that allows predictions to be made concerning the life expectancies following various extents of surgical resection of gliomas of all grades of malignancy. The key model parameters are the growth rate and the diffusion rate. These rates were initially derived from analysis of a case of recurrent anaplastic astrocytoma treated by chemotherapies. Numerical simulations allow us to estimate what would have happened to that patient if various extents of surgical resection, rather than chemotherapies, had been used. In each case, the shell of the infiltrating tumour that remains after 'gross total removal' or even a maximal excision continues to grow and regenerates the tumour mass remarkably rapidly. By developing a model that allows the growth and diffusion rates to define the distribution of cells at the time of diagnosis, and then varying these rates by about 50%, we created a hypothetical tumour patient population whose survival times show good agreement with the results recently reported by Kreth for treatments of glioblastomas. Tenfold decreases in the rates of growth and diffusion mimic the results reported by many other investigators with more slowly growing gliomas. Thus, the model quantitatively supports the ideas that (i) gliomas infiltrate so diffusely that they cannot be cured by resection alone, surgical or radiological, no matter how extensive that may be; (ii) the more extensive the resection, regardless of the degree of malignancy of the glioma, the greater the life expectancy; and (iii) measurements of the two rates, growth and diffusion, may be able to predict survival rates better than the current histological estimates of the type and grade of gliomas.

Early postoperative magnetic resonance imaging following nonneoplastic cortical resection

Postcraniotomy residual tumor is often determined by magnetic resonance (MR) imaging. Magnetic resonance changes that occur in the postoperative setting must be defined to ensure both the optimum timing of postoperative image acquisition and the accurate assessment of images for residual tumor. Postoperative changes in nontumor parenchyma have previously been described for computerized tomography but not for MR imaging. In the present study, 11 patients without intracranial neoplastic disease (six females and five males with a median age of 36 years) submitted to MR imaging 17 to 28 hours after undergoing temporal lobectomies for epilepsy. Four of the operations were performed with the patients under general anesthesia and seven under local anesthesia. Postoperative MR images (T1-weighted, T1-weighted gadolinium enhanced, and T2-weighted) were reviewed. Extraaxial fluid, air, or blood was present in all cases. Enhancement of the resection bed parenchyma occurred in seven (64%) of 11 patients. In three of the remaining four patients, assessment of parenchymal enhancement was obscured by extraaxial fluid collections. Dural enhancement occurred adjacent to the resection site in all of the cases and remotely in 73%. Eight (73%) of 11 patients displayed enhancement of the pia-arachnoid of the ipsilateral cerebral convexity, two (18%) of the contralateral convexity, and four (36%) of the pia-arachnoid overlying the cerebellum. Contrary to previous reports, contrast enhancement of nonneoplastic human brain parenchyma can occur postoperatively within 17 hours. Benign parenchymal contrast enhancement is usually linear in appearance; nonneoplastic dural and leptomeningeal enhancement can occur both adjacent to and distant from the surgical site. Extraaxial fluid collections can hinder MR evaluation of the resection bed.

Malignant gliomas in children

Childhood supratentorial malignant gliomas, though less common than those in adults, are responsible for disproportionately high morbidity and mortality rates. Important advances have been made in our ability to diagnose these tumors by noninvasive neuroimaging techniques. In addition, progress has been made in our ability to correlate pathology and biological features with clinical outcomes to provide prognostic information. Neuroimaging and tissue prognostic factors now have important roles which directly affect clinical management. While surgery and radiation therapy are critical components of the treatment of childhood supratentorial gliomas, the role of chemotherapy is less clear. Significant responses have been demonstrated for chemotherapy regimens in infants with malignant gliomas and high-dose chemotherapy and ABMR regimens also produce encouraging response rates. The results of current clinical trials will help us determine if these response rates will translate into prolonged patient survival and allow us to identify subgroups of childhood malignant glioma patients that may benefit from adjuvant chemotherapy.

Longer survival in high grade gliomas: intraoperative radiation therapy (IORT) and immunocytochemical assessment of their growth potential

The authors report prolonged survival in patients with high grade (grade 3 and 4) gliomas who were given additional intraoperative radiation therapy (IORT) and discuss survival in relation to the immunocytochemical assessment of their tumours. Of 54 selected patients with high grade gliomas treated with multimodal therapy including IORT during the years from 1985 to 1989, 11 had long-term survival over 5 years after the initial treatment. The clinicopathological features, analysed retrospectively, that were associated with prolonged survival were: (1) epileptic seizures, (2) initial CT scans showing a small mass without contrast enhancement which developed into an enhancing larger mass on follow up, (3) tumour location which was frequently frontal and near the cortical surface, (4) 20-30 Gy irradiation (mean 25.5 Gy) in IORT delivered in one fraction to the post-resection tumour bed, and (5) a low proliferating cell nuclear antigen (PCNA) labelling index (LI). The most favourable prognostic indicator was found to be a low PCNA LI.

Correlation of intra-operative ultrasound with histopathologic findings after tumour resection in supratentorial gliomas. A method to improve gross total tumour resection

The aim of this study was to evaluate whether intra-operative ultrasound (= IOUS) is a suitable tool to detect residual tumour tissue after gross total resection in supratentorial gliomas. During a period of 18 months 45 patients with supratentorial gliomas (38 high-grade and 9 low-grade, according to the WHO-grading system [42]) were operated on. A series of 78 biopsies was taken from the resection cavity under continuous sonographic control at the end of surgery. Gross total tumour resection was intended in 34 patients (= 76%). The biopsy specimens were matched with the sonographic features at each biopsy site. The sonographic appearance of the resection margins were classified into 2 groups: (1) Irregular hyperechoic areas extending from the cavity into the iso-echogenic brain tissue and (2) a dense small (< or = 3 mm in diameter) rather regular hyperechoic rim surrounding the resection cavity. 47 out of 53 biopsies taken from hyperechoic areas (group I) (36 high-grade/11 low-grade) revealed solid tumour tissue (= 89%). 34 (= 72%) of these 47 areas were microscopically assessed as inconspicuous by the surgeon. 6 samples (4 high-grade/2 low-grade) contained tumour infiltration zone. 25 biopsies (23 high-grade/2 low-grade) taken from the hyperechoic rim [group 2] were diagnosed as follows: Normal brain tissue in 11, tumour infiltration zone in 8 and solid tumour tissue in 6 cases. Of 34 cases with "gross total removal" according to the surgeon's assessment 25 showed sonographic signs of residual tumour tissue, which was confirmed histologically as solid tumour tissue in 22 of these cases. It is concluded, that IOUS following resection of supratentorial gliomas can detect residual tumour tissue with high specificity and thus improve gross total resection. However, a thin hyperechoic rim surrounding the resection cavity (less than 3 mm in diameter) is a non-specific finding, which can mask thin residual tumour layers and therefore needs further evaluation of its nature.

Tumor and target delineation: current research and future challenges

In the past decade, significant progress has been made in the imaging of tumors, three dimensional (3D) treatment planning, and radiation treatment delivery. At this time one of the greatest challenges for conformal radiation therapy is the accurate delineation of tumor and target volumes. The physician encounters many uncertainties in the process of defining both tumor and target. The sources of these uncertainties are discussed, as well as the issues requiring study to reduce these uncertainties.

Invading C6 glioma cells maintaining tumorigenicity

To characterize rat glioma cell invasion, 2 x 10(6) fluorophore-labeled or transfection-labeled C6 rat glioma cells were implanted in the rat frontal lobe. Eighty percent of the rats implanted formed bulk tumors (3-4 mm in diameter). Two weeks after implantation, fluorescence microscopy revealed single tumor cells in sites over 16 mm from the bulk brain tumor. Tumor cells distant from the bulk tumor remained single without mass formation and invaded primarily along white matter tracts. Two weeks after tumor implantation, three cell lines were created from each brain by disaggregation and initiation in culture of 1) bulk tumor, 2) contralateral hemisphere, and 3) cerebellum; all disaggregated specimens generated viable cultures. Cells cultured from the contralateral hemisphere were morphologically indistinguishable from cells from the bulk tumor and from the original C6 cell line. Cells cultured from the cerebellum were morphologically quite distinct from the C6 cell line. Cells from disaggregated specimens obtained from the tumor, contralateral hemisphere, and cerebellum were implanted in the frontal lobe of naive rats to test tumorgenicity. Bulk tumor formed in 58% of the rats implanted with specimens from tumor, in 75% of the rats implanted with specimens from contralateral hemisphere, and in only 12.5% of the rats implanted with specimens from the cerebellar hemispheres. Experiments using C6 cells labeled by transfection with the p3' ss DNA vector prior to implantation confirmed that the cells cultured from the contralateral hemisphere were derived from the implanted C6 cells. Experiments with C6 cells anchored in agar served to verify that movement to the contralateral hemisphere was secondary to parenchymal invasion rather than dispersion in the cerebrospinal fluid.

Local delivery of the topoisomerase I inhibitor camptothecin sodium prolongs survival in the rat intracranial 9L gliosarcoma model

Camptothecin, a naturally occurring inhibitor of the DNA-replicating enzyme topoisomerase I, demonstrated promising anti-tumor activity in pre-clinical testing; however, because of unexpected toxicity and low anti-tumor effects in the initial clinical trials, further testing was discontinued. We hypothesized that local controlled delivery of camptothecin sodium would achieve effective concentrations in brain tumors without the observed systemic side effects, thereby allowing this novel drug to be used to treat patients with malignant gliomas. To test this hypothesis, we evaluated the sensitivity of rat glioma lines and established human glioma lines to camptothecin in vitro. We found that the LD90 for the established rat and human lines was 0.3 to 1.4 microM after a 1 hr exposure and decreased to less than 0.1 microM after continuous exposure for 7 days. We loaded camptothecin into a controlled-release polymer (ethylene-vinyl acetate co-polymer; EVAc) and showed by high-pressure liquid chromatography that controlled release occurred over at least 21 days. We then tested camptothecin against 9L gliosarcoma, implanted into the brain of Fischer 344 rats. Five days after tumor implantation, animals were treated with camptothecin delivered either systemically or locally by release from EVAc. Local controlled delivery by the polymer significantly extended survival: 59% of the treated animals were long-term survivors (> 120 days) compared to 0% of controls. Systemic administration did not extend survival compared to controls. We compared the efficacy of camptothecin delivered locally with a polymer to camptothecin injected directly into the tumor. Camptothecin increased survival only when delivered locally by polymer.

Expression of N-cadherin and alpha-catenin in astrocytomas and glioblastomas

We examined levels of mRNA and protein for N-cadherin, the predominant cadherin in neural tissues, and mRNA levels for the cadherin-associated protein, alpha-catenin, in a series of gliomas and in glioblastoma cell lines. mRNA levels for N-cadherin and alpha-catenin were significantly higher in glioblastomas than in low-grade astrocytomas or normal brain, while the levels of intact N-cadherin protein were similar in glioblastomas, low-grade astrocytomas and brain. In addition, there was no consistent relationship between invasiveness and expression of N-cadherin and alpha-catenin in highly invasive vs minimally invasive tumours within the same histopathological grade. To assess further the relationship between cadherin expression and neural tumour invasion, we measured N-cadherin expression, calcium-dependent cell adhesion and motility of several glioblastoma cell lines. While all N-cadherin-expressing lines were adhesive, no correlation was seen between the level of N-cadherin expression and cell motility. Together, these findings imply that, in contrast to the role played by E-cadherin in carcinomas, N-cadherin does not restrict the invasion of glioblastomas.

Substrates for astrocytoma invasion

A better understanding of the influences of specific extracellular substrates, including proteins, glycosaminoglycans, and parenchymal cells, on the invasive behavior of glioma cells would potentially lead to novel forms of treatment aimed at confining the tumor. A monolayer, microliter scale assay was used to investigate how different substrates influenced glioma migration. Basal or unspecific movement (range, 10-260 microns/d) was determined by observing a panel of seven established human glioma cell lines. Migration rates two to five times higher than this basal activity were referred to as preferential and specific glioma migration; these rates generally occurred on merosin and tenascin. Collagen, fibronectin, or vitronectin were less supportive of migration. The glioma cells migrated on hyaluronic acid, but they did not migrate to the extent generally found on the extracellular matrix proteins. Glioma-derived extracellular matrix also served to promote cell migration. This finding implicates a role for either glioma remodeling or synthesis of a permissive environment for local dissemination that may be independent of the constitutive matrix proteins normally found in the brain. Although the glioma cells were able to migrate over monolayers of other glioma cells, they were unable to migrate over astrocytes and fibroblasts. Our findings indicate that the invasive behavior of glioma cells in situ is most likely a consequence of the interplay between the cells' manipulation of the environment and the constitutive ligands associated with specific regions or structures of the brain.

Immunolocalization of cathepsin B in human glioma: implications for tumor invasion and angiogenesis

The poor prognosis of patients with malignant gliomas is at least partially due to the invasive nature of these tumors. In this study, the authors investigated the possibility that the cysteine protease cathepsin B (CB) is a participant in the process of glial tumor cell invasion. To accomplish this, an immunohistochemical analysis was made of the localization of antibodies to CB in biopsies of five specimens of normal brain, 16 astrocytomas, 33 anaplastic astrocytomas, and 33 glioblastomas multiforme. Staining was scored according to the percentage of positive cells and the intensity of the stain, graded from 0 to 3+. Staining for CB was not seen in any of five samples of normal brain except for occasional neuronal cell bodies and microglia. Only five (31%) of 16 astrocytomas showed a small percentage of positive cells (0.01%-3%) that were stained in a light, diffuse cytoplasmic pattern (1+). Twenty-nine (87.8%) of 33 anaplastic astrocytomas showed positive light, granular staining in 2% to 40% of cells. In anaplastic astrocytoma, the staining within a tumor was heterogeneous with intensities of 1+ (17%), 1+ to 2+ (29%), or 2+ (55%). In contrast, all 33 (100%) glioblastomas were positive in 10% to 90% of cells. The staining was present in a coarse, granular pattern with an intensity of 2+ (12%) or 3+ (88%). Tumor cells infiltrating into brain adjacent to malignant gliomas stained positively in 26 cases that could be evaluated for glioblastoma multiforme; these invading cells frequently followed penetrating blood vessels as typical "secondary structures of Scherer." Moderate to intense CB staining associated with endothelial proliferation in high-grade tumors was also observed, especially in regions of tumor infiltration into adjacent normal brain. These results provide evidence consistent with the hypothesis that CB is functionally significant in the process of tumor invasion and angiogenesis in the clinical progression of the malignant phenotype in astrocytes.

Performance of sulfhydryl boron hydride in patients with grade III and IV astrocytoma: a basis for boron neutron capture therapy

This study investigated the rationale of boron neutron capture therapy (BNCT) for the treatment of Grade III and IV astrocytoma. The European Community joint research program on BNCT plans to use sulfhydryl boron hydride (BSH) in clinical trials. The work presented here, examines the performance of BSH in eight patients with Grade III and IV astrocytoma using a measurement technique which precisely correlates the boron uptake with the histology of the tumor and the peritumoral brain. Astrocytomas are exceptionally heterogeneous and spread migrating tumor cells into the surrounding brain. The patients were infused with 50 mg BSH per kilogram of body weight at 12, 18, 24 or 48 hours before surgery. At the time of operation, specimens were obtained of the tumor, skin, muscle, dura, blood, urine, and, when surgically possible, the brain adjacent to tumor. In three patients the intracellular boron distribution was investigated by subcellular fractionation. The blood clearance was biphasic with half-lives of 0.6 and 8.2 hours. After 3 days, approximately 70% of the dose injected was excreted in the urine. The maximum boron concentration in the tumor was 20 ppm, 12 hours after the infusion. The tumor-to-blood ratios ranged between 0.2 and 1.4, with the highest values after 18 to 24 hours. In the brain specimens the boron concentration never exceeded 1 ppm. This work confirms a selective uptake of boron in the tumor compared to the surrounding brain and that boron, to some extent, is incorporated in the tumor cells.

The in vitro motility of human gliomas increases with increasing grade of malignancy

BACKGROUND

Malignant gliomas are a highly invasive disease with a dismal prognosis despite aggressive therapeutic interventions.

METHODS

The authors tested the hypothesis that increasing in vitro motility of human glial tumors correlates with increasing grade of malignancy. A radial dish assay was used to quantitatively assess the brain tumor cell motility of 14 low passage cell lines derived from human glial tumors of varied malignancy, and 3 cell lines derived from human glia. The egress of cells from a central region of high tumor cell density to a region of lower tumor cell density was determined at various time points. A motility coefficient (MC), the slope of distance traveled against time, was generated by simple linear regression analysis.

RESULTS

The MC increased with the increased histologic grade of malignancy. Generation of a t-statistic was used to determine the significance of differences in motility among 5 histopathologic groups: 10 glioblastoma (World Health Organization Grade IV) cell lines (mean MC, 0.00396), 2 mixed anaplastic oligoastrocytoma (Grade III) cell lines (mean MC, 0.00382), 1 anaplastic astrocytoma (Grade III) cell line (mean MC, 0.00295), 1 Grade I glioma cell line (mean MC, 0.00206), and 3 human glial cell lines (mean MC, 0.00110).

CONCLUSIONS

The radial dish assay provided a reproducible method for quantitatively assessing brain tumor cell motility. The higher MC observed with the malignant human glioma cell lines correlated with the tendency of these tumors to invade into adjacent brain tissue. The potential to inhibit glial tumor motility may provide an important therapeutic avenue in the future.

Assessment of brain tumor cell motility in vivo and in vitro

Brain tumor dispersal far from bulk tumor contributes to and, in some instances, dominates disease progression. Three methods were used to characterize brain tumor cell motility in vivo and in vitro: 1) 2 weeks after implantation in rat cerebral cortex, single C6 cells labeled with a fluorescent tag had migrated to brain sites greater than 16 mm distant from bulk tumor; 2) time-lapse videomicroscopy of human brain tumor cells revealed motility of 12.5 microns/hr. Ruffling leading edges and pseudopod formation were most elaborate in more malignant cells; 3) an in vitro assay was devised to quantitatively evaluate motility from a region of high cell density to one of lower cell density. Human brain tumor cells were plated in the center of a petri dish, washed, and refed, establishing a 2-cm circular zone of cells in the dish center. Motility was determined by counting cells daily at predetermined distances from the central zone perimeter. Cells were found 1 cm from the perimeter by 24 hours and 3 cm from the perimeter by 4 days. Increasing serum concentration increased motility; however, neither fibronectin nor arrest of cells in the G0 phase by hydroxyurea altered motility. The addition of cytochalasin B to block cytoskeletal assembly prevented cell motility. Motility increased with increased malignancy. Subpopulations of cells were created by clonal amplification of cells that had migrated most rapidly to the dish periphery. Although morphologically indistinguishable when compared to the original cell line from which they were derived, these subpopulations demonstrated significantly increased motility.

Radiation necrosis or glioma recurrence: is computer-assisted stereotactic biopsy useful?

Fifty-one patients with supratentorial glioma treated with external beam radiotherapy (median dose 59.5 Gy) who then demonstrated clinical or radiographic evidence of disease progression underwent stereotactic biopsy to differentiate tumor recurrence from radiation necrosis. The original tumor histological type was diffuse or fibrillary astrocytoma in 21 patients (41%), oligodendroglioma in 13 (26%), and oligoastrocytoma in 17 (33%); 40 tumors (78%) were low-grade (Kernohan Grade 1 or 2). The median time to suspected disease progression was 28 months. Stereotactic biopsy showed tumor recurrence in 30 patients (59%), radiation necrosis in three (6%), and a mixture of both in 17 (33%); one patient (2%) had a parenchymal radiation-induced chondroblastic osteosarcoma. The tumor type at stereotactic biopsy was similar to the original tumor type and was astrocytoma in 24 patients (47%), oligodendroglioma in eight (16%), oligoastrocytoma in 16 (31%), unclassifiable in two (4%), and chondroblastic osteosarcoma in one patient (2%). At biopsy, however, only 19 tumors (37%) were low grade (Kernohan Grade 1 or 2). Subsequent surgery confirmed the stereotactic biopsy histological findings in eight patients. Follow-up examination showed 14 patients alive with a median survival of 1 year for the entire group. Median survival times after biopsy were 0.83 year for patients with tumor recurrence and 1.86 years for patients with both tumor recurrence and radionecrosis; these findings were significantly different (p = 0.008, log-rank test). No patient with radiation necrosis alone died. Other factors associated with reduced survival were a high proportion of residual tumor (p = 0.024), a low proportion of radionecrosis (p < 0.001), and a Kernohan Grade of 3 or 4 (p = 0.005). In conclusion, in patients with previously irradiated supratentorial gliomas in whom radionecrosis or tumor recurrence was clinically or radiographically suspected, results of stereotactic biopsy could be used to differentiate tumor recurrence, radiation necrosis, a mixture of both lesions, or radiation-induced neoplasm. In addition, biopsy results could predict survival rates.

Effectiveness of intraoperative radiation therapy for recurrent supratentorial low grade glioma

Twelve adult patients in the records of 38 patients with histologically verified supratentorial low grade glioma showed recurrence at the Gifu University Hospital between 1980 and 1992. A mean period to recurrence from the initial surgery and postoperative radiation was 38 months. Six of these patients underwent intraoperative radiation therapy. The other six patients received chemotherapy with conventional cytoreductive surgery in three cases and additional external irradiation in three cases. The 2-year survival rate of the former patients was 83.8% and significantly higher than that of the latter ones, 16.7% (p < 0.05). Most cases showing recurrence of supratentorial low grade glioma were occurred locally, and dissemination or remote metastasis of the lesion were rare. The results revealed that the local control is important for recurrent tumors of supratentorial low grade gliomas. The effectiveness of the intraoperative radiation therapy as the second operation for the recurrent supratentorial benign glioma is discussed.